Sachs Madass 125 ?

[renault_megane_dci]

I suggest changing the front brake to something beefier since the bike will probably put on weight ...

[woodsrat]

I mentioned a cheap voltage regulator I use when I build my AC wiring setups for the Lifan motors. It's sold through the Tucker Rocky Off-Road catalog and officially it's known as the "MSRHP Universal Voltage Regulator", p/n 74-4603, and retails for $14.45. So far it's worked flawlessly and I've not blown a bulb.

I have the wiring diagram I use on paper and scanned it. If you'd like a copy PM me your email address. It's incredibly simple and once folks see it they slap themselves on the head and say "why didn't I know that???"

I wish small bikes had reliable stuff like this when I was a kid. I went through 6v. tail light bulbs by the gross and headlights weren't far behind yet they still only put out about a tenth of the light my $8 Harbor Freight halogen tractor light puts out. Same goes for the $10 LED tail light.

[BobS]

Hey guys
You might want to hold up on this project for a bit. Yamaha just came out with a 125cc motorcycle that gets 188 mpg. Check this out:
Yamaha shows retro lightweight 125cc motorcycle that gets 220 mpg
Damn, they keep on like this and they could ruin all our fun.
Bob

[sendler]

They are showing it but it may never be produced.

[woodsrat]

Yes, it was shown at the Tokyo Motor Show three years ago along with the Yamaha XTW-250 "Ryoku" sport-utilility motorcycle that everyone went nuts over--and wasn't produced, either.

I'd still like to see them build a 220 MPG motorcycle.

[PeterS]

Originally Posted by woodsrat

Yes, it was shown at the Tokyo Motor Show three years ago along with the Yamaha XTW-250 "Ryoku" sport-utilility motorcycle that everyone went nuts over--and wasn't produced, either.

I'd still like to see them build a 220 MPG motorcycle.

You better include weight and speed into those parameters, 220 mpg would be easy at 30 mph.

[ProDigit]

I don't know what benefit aerodynamics have on a 110cc bike, seeing it barely passes 55MPH.
THe aerodynamic drag reduction you get from using the plastic frame, is compensated by the added weight for start-stopping the bike.
An aerodynamic frame like that makes sense if your cruising speed exceeds 45MPH. A 110cc cruises best between 35-40MPH, at about 3-4k RPM.
Taking it beyond 40MPH will hurt MPG.

I would think that a 110 can get 125MPG easily.
When maintaining 35-40MPH it might even reach 150MPG.
200MPG is a bit optimistic, unless the engine is ran in the 2,5k rpm range, if it could pull the load..

[PeterS]

Originally Posted by ProDigit

I don't know what benefit aerodynamics have on a 110cc bike, seeing it barely passes 55MPH.
THe aerodynamic drag reduction you get from using the plastic frame, is compensated by the added weight for start-stopping the bike.
An aerodynamic frame like that makes sense if your cruising speed exceeds 45MPH. A 110cc cruises best between 35-40MPH, at about 3-4k RPM.
Taking it beyond 40MPH will hurt MPG.

I would think that a 110 can get 125MPG easily.
When maintaining 35-40MPH it might even reach 150MPG.
200MPG is a bit optimistic, unless the engine is ran in the 2,5k rpm range, if it could pull the load..

Which is where the aero fairing comes in.... reduce the drag and the frontal area so you need less power to push you through the air the same speed or have more power available to go faster.

A CT`110 Honda, pretty similar to a Madass has 9.5 bhp max but with the right fairing should be able to tour at 55 or 60 mph.

[ProDigit]

If your main objective is long rides at 50+MPH speeds, you're better off with a 250cc running at lower RPM.

A 110cc is running at the peak performance at 50-55MPH, which is hardly MPG friendly.

A 110cc is made for the city.
A lot of start-stops.
Fairings make it harder for the bike to start or stop, because they add weight to the bike.

[PeterS]

I think we'll have to disagree a little PD. Increasing aerodynamic efficiency means less power is required. The little extra weight doesn't make much difference, the aero efficiency does.

The calculator at the top of the page says that with a CDA of 3.15 ft2 / 0.29 m2 ( a drag coefficient of .45 and a frontal area of 7 squ feet) which seems achievable. That requires 4.6 hp to do 60 mph / 97 kmh. The roll coefficient I used is .02.

I'm not sure how accurate the calculator is but it's a reasonable indicator.